This invention relates to a method of, and apparatus for, controlling an automatic embroidery machine.
Originally, embroidery machines used punched cards and/or paper tape data to produce the pantograph x/y movements required to stitch embroidery designs. Users were limited to costly preprogrammed designs that took days or weeks to be prepared by the punch houses.
Because many users wished to produce individual monograms or names, alone or in combination with designs (e(e for uniforms), a demand arose for lettering systems to be supplied with embroidery machines. These were initially fulfilled by electronic keyboard apparatus, which has preset sizes of various font styles of lettering stored in them. The user could choose a style and size, and type in the letters to be sewn. However, there was no ability to chancre sizes on a continuous scale, to alter parameters such as density and column width, or to put lettering on a curve and so on.
Eventually computer software systems were introduced (in the past 10 years or so). One main advantage was to make it easier to send design data to embroidery machines by using disks rather than paper tape. Another advantage was to allow users to manipulate preprogrammed designs, for example to rotate them, to mirror them, to resize them, to combine them, to see the effects of colour changes and to save altered designs as new designs. Some of these functions were previously available directly on the embroidery machines, but there was no way to visualise a change before it was implemented, which could be costly if there was a mistake, and this would lead to a waste of time and possibly to ruining garments being embroidered.
Embroidery is a three-dimensional product, the stitches of an embroidered letter (or any other design) covering a two-dimensional area, and also `sitting` on top of the material to provide the third dimension (`height`). Different types of material can affect the three-dimensional appearance of embroidery stitched thereon. In this connection, there are two important elements, namely the depth of pile (or `thickness`) of the material, and the elasticity (or `stretch`) of the material.
As the pile or thickness increases, embroidery stitches tend to `sink` into the material, so the same lettering would look flatter on a heavy pile fabric than on a flat woven one. Similarly, as materials become more elastic, embroidery stitches tend to pull in along their length and make the lettering look thinner. Neither of these effects is desirable. In many materials, the effects are interconnected, as when fabrics get thicker they often get more elastic
The density of the stitches in the lettering can be adjusted to reduce the tendency of stitches to sink into fabric. One known way of doing this is to use the settings in a monogramming program. The program then calculates the number of stitches that are required to be placed for each of the letters of the design to be embroidered. A disadvantage of this method is that the operator must be an expert.